Tooth #20 – Lower left second premolar
5th tooth back from the middle, lower left.
- International
- 35
- Palmer
- 5
- Type
- Premolar
- Roots
- 1
- Canals
- usually 1
- Comes in
- 11–12 years
The second of the two premolars on the lower left, just in front of the first molar.
- In front: #21 lower left first premolar
- Behind: #19 lower left first molar
- Same tooth on the other side: #29 lower right second premolar
- Bites against: #13 upper left second premolar
It replaces the lower left baby second molar (K), which falls out at 10–12 years.
Usually one root (1–3) and usually one canal (1–3).
Lower second premolars: roots, canals and the studies behind the counts →
This tooth is #20 in the US and 35 in the international (FDI) system, where the 3 means the lower left quarter and the 5 is its place counting from the front.
There's no international tooth 20, because those numbers always have two digits.
American Dental Association 2024; Harris 2005; American Dental Association 2012. Full titles are on the About page.